xref: /XiangShan/src/main/scala/xiangshan/backend/decode/FPDecoder.scala (revision 34f9ccd0e235272c39ecb1ab5320cef847d56a8a)
1/***************************************************************************************
2* Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
3* Copyright (c) 2020-2021 Peng Cheng Laboratory
4*
5* XiangShan is licensed under Mulan PSL v2.
6* You can use this software according to the terms and conditions of the Mulan PSL v2.
7* You may obtain a copy of Mulan PSL v2 at:
8*          http://license.coscl.org.cn/MulanPSL2
9*
10* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
11* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
12* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
13*
14* See the Mulan PSL v2 for more details.
15***************************************************************************************/
16
17package xiangshan.backend.decode
18
19import org.chipsalliance.cde.config.Parameters
20import chisel3._
21import chisel3.util._
22import freechips.rocketchip.rocket.DecodeLogic
23import freechips.rocketchip.rocket.Instructions._
24import xiangshan.backend.decode.isa.bitfield.XSInstBitFields
25import xiangshan.backend.fu.fpu.FPU
26import xiangshan.backend.fu.vector.Bundles.{VSew, VLmul}
27import xiangshan.backend.Bundles.VPUCtrlSignals
28import xiangshan.{FPUCtrlSignals, XSModule}
29
30class FPToVecDecoder(implicit p: Parameters) extends XSModule {
31  val io = IO(new Bundle() {
32    val instr = Input(UInt(32.W))
33    val vpuCtrl = Output(new VPUCtrlSignals)
34  })
35
36  val inst = io.instr.asTypeOf(new XSInstBitFields)
37  val fpToVecInsts = Seq(
38    FADD_S, FSUB_S, FADD_D, FSUB_D,
39    FEQ_S, FLT_S, FLE_S, FEQ_D, FLT_D, FLE_D,
40    FMIN_S, FMAX_S, FMIN_D, FMAX_D,
41    FMUL_S, FMUL_D,
42    FDIV_S, FDIV_D, FSQRT_S, FSQRT_D,
43    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S, FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
44    FCLASS_S, FCLASS_D, FSGNJ_S, FSGNJ_D, FSGNJX_S, FSGNJX_D, FSGNJN_S, FSGNJN_D,
45
46    // scalar cvt inst
47    FCVT_W_S, FCVT_WU_S, FCVT_L_S, FCVT_LU_S,
48    FCVT_W_D, FCVT_WU_D, FCVT_L_D, FCVT_LU_D, FCVT_S_D, FCVT_D_S,
49    FMV_X_W, FMV_X_D,
50  )
51  val isFpToVecInst = fpToVecInsts.map(io.instr === _).reduce(_ || _)
52  val isFP32Instrs = Seq(
53    FADD_S, FSUB_S, FEQ_S, FLT_S, FLE_S, FMIN_S, FMAX_S,
54    FMUL_S, FDIV_S, FSQRT_S,
55    FMADD_S, FMSUB_S, FNMADD_S, FNMSUB_S,
56    FCLASS_S, FSGNJ_S, FSGNJX_S, FSGNJN_S,
57  )
58  val isFP32Instr = isFP32Instrs.map(io.instr === _).reduce(_ || _)
59  val isFP64Instrs = Seq(
60    FADD_D, FSUB_D, FEQ_D, FLT_D, FLE_D, FMIN_D, FMAX_D,
61    FMUL_D, FDIV_D, FSQRT_D,
62    FMADD_D, FMSUB_D, FNMADD_D, FNMSUB_D,
63    FCLASS_D, FSGNJ_D, FSGNJX_D, FSGNJN_D,
64  )
65  val isFP64Instr = isFP64Instrs.map(io.instr === _).reduce(_ || _)
66  // scalar cvt inst
67  val isSew2Cvts = Seq(
68    FCVT_W_S, FCVT_WU_S, FCVT_L_S, FCVT_LU_S,
69    FCVT_W_D, FCVT_WU_D, FCVT_S_D, FCVT_D_S,
70    FMV_X_W,
71  )
72  val isSew2Cvt = isSew2Cvts.map(io.instr === _).reduce(_ || _)
73  val isLmulMf4Cvts = Seq(
74    FCVT_W_S, FCVT_WU_S,
75    FMV_X_W,
76  )
77  val isLmulMf4Cvt = isLmulMf4Cvts.map(io.instr === _).reduce(_ || _)
78  val needReverseInsts = fpToVecInsts
79  val needReverseInst = needReverseInsts.map(_ === inst.ALL).reduce(_ || _)
80  io.vpuCtrl := 0.U.asTypeOf(io.vpuCtrl)
81  io.vpuCtrl.fpu.isFpToVecInst := isFpToVecInst
82  io.vpuCtrl.fpu.isFP32Instr   := isFP32Instr
83  io.vpuCtrl.fpu.isFP64Instr   := isFP64Instr
84  io.vpuCtrl.vill  := false.B
85  io.vpuCtrl.vma   := true.B
86  io.vpuCtrl.vta   := true.B
87  io.vpuCtrl.vsew  := Mux(isFP32Instr || isSew2Cvt, VSew.e32, VSew.e64)
88  io.vpuCtrl.vlmul := Mux(isFP32Instr || isLmulMf4Cvt, VLmul.mf4, VLmul.mf2)
89  io.vpuCtrl.vm    := inst.VM
90  io.vpuCtrl.nf    := inst.NF
91  io.vpuCtrl.veew := inst.WIDTH
92  io.vpuCtrl.isReverse := needReverseInst
93  io.vpuCtrl.isExt     := false.B
94  io.vpuCtrl.isNarrow  := false.B
95  io.vpuCtrl.isDstMask := false.B
96  io.vpuCtrl.isOpMask  := false.B
97}
98
99
100class FPDecoder(implicit p: Parameters) extends XSModule{
101  val io = IO(new Bundle() {
102    val instr = Input(UInt(32.W))
103    val fpCtrl = Output(new FPUCtrlSignals)
104  })
105
106  private val inst: XSInstBitFields = io.instr.asTypeOf(new XSInstBitFields)
107
108  def X = BitPat("b?")
109  def N = BitPat("b0")
110  def Y = BitPat("b1")
111  val s = BitPat(FPU.S)
112  val d = BitPat(FPU.D)
113  val i = BitPat(FPU.D)
114
115  val default = List(X,X,X,N,N,N,X,X,X)
116
117  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
118  val single: Array[(BitPat, List[BitPat])] = Array(
119    // IntToFP
120    FMV_W_X  -> List(N,i,s,Y,N,Y,N,N,N),
121    FCVT_S_W -> List(N,i,s,Y,Y,Y,N,N,Y),
122    FCVT_S_WU-> List(N,i,s,Y,Y,Y,N,N,Y),
123    FCVT_S_L -> List(N,i,s,Y,Y,Y,N,N,Y),
124    FCVT_S_LU-> List(N,i,s,Y,Y,Y,N,N,Y),
125    // FPToInt
126    FMV_X_W  -> List(N,d,i,N,N,N,N,N,N), // dont box result of fmv.fp.int
127    FCLASS_S -> List(N,s,i,N,N,N,N,N,N),
128    FCVT_W_S -> List(N,s,i,N,Y,N,N,N,Y),
129    FCVT_WU_S-> List(N,s,i,N,Y,N,N,N,Y),
130    FCVT_L_S -> List(N,s,i,N,Y,N,N,N,Y),
131    FCVT_LU_S-> List(N,s,i,N,Y,N,N,N,Y),
132    FEQ_S    -> List(N,s,i,N,Y,N,N,N,N),
133    FLT_S    -> List(N,s,i,N,Y,N,N,N,N),
134    FLE_S    -> List(N,s,i,N,Y,N,N,N,N),
135    // FPToFP
136    FSGNJ_S  -> List(N,s,s,N,N,Y,N,N,N),
137    FSGNJN_S -> List(N,s,s,N,N,Y,N,N,N),
138    FSGNJX_S -> List(N,s,s,N,N,Y,N,N,N),
139    FMIN_S   -> List(N,s,s,N,Y,Y,N,N,N),
140    FMAX_S   -> List(N,s,s,N,Y,Y,N,N,N),
141    FADD_S   -> List(Y,s,s,N,Y,Y,N,N,N),
142    FSUB_S   -> List(Y,s,s,N,Y,Y,N,N,N),
143    FMUL_S   -> List(N,s,s,N,Y,Y,N,N,N),
144    FMADD_S  -> List(N,s,s,N,Y,Y,N,N,N),
145    FMSUB_S  -> List(N,s,s,N,Y,Y,N,N,N),
146    FNMADD_S -> List(N,s,s,N,Y,Y,N,N,N),
147    FNMSUB_S -> List(N,s,s,N,Y,Y,N,N,N),
148    FDIV_S   -> List(N,s,s,N,Y,Y,Y,N,N),
149    FSQRT_S  -> List(N,s,s,N,Y,Y,N,Y,N)
150  )
151
152
153  // isAddSub tagIn tagOut fromInt wflags fpWen div sqrt fcvt
154  val double: Array[(BitPat, List[BitPat])] = Array(
155    FMV_D_X  -> List(N,i,d,Y,N,Y,N,N,N),
156    FCVT_D_W -> List(N,i,d,Y,Y,Y,N,N,Y),
157    FCVT_D_WU-> List(N,i,d,Y,Y,Y,N,N,Y),
158    FCVT_D_L -> List(N,i,d,Y,Y,Y,N,N,Y),
159    FCVT_D_LU-> List(N,i,d,Y,Y,Y,N,N,Y),
160    FMV_X_D  -> List(N,d,i,N,N,N,N,N,N),
161    FCLASS_D -> List(N,d,i,N,N,N,N,N,N),
162    FCVT_W_D -> List(N,d,i,N,Y,N,N,N,Y),
163    FCVT_WU_D-> List(N,d,i,N,Y,N,N,N,Y),
164    FCVT_L_D -> List(N,d,i,N,Y,N,N,N,Y),
165    FCVT_LU_D-> List(N,d,i,N,Y,N,N,N,Y),
166    FCVT_S_D -> List(N,d,s,N,Y,Y,N,N,Y),
167    FCVT_D_S -> List(N,s,d,N,Y,Y,N,N,Y),
168    FEQ_D    -> List(N,d,i,N,Y,N,N,N,N),
169    FLT_D    -> List(N,d,i,N,Y,N,N,N,N),
170    FLE_D    -> List(N,d,i,N,Y,N,N,N,N),
171    FSGNJ_D  -> List(N,d,d,N,N,Y,N,N,N),
172    FSGNJN_D -> List(N,d,d,N,N,Y,N,N,N),
173    FSGNJX_D -> List(N,d,d,N,N,Y,N,N,N),
174    FMIN_D   -> List(N,d,d,N,Y,Y,N,N,N),
175    FMAX_D   -> List(N,d,d,N,Y,Y,N,N,N),
176    FADD_D   -> List(Y,d,d,N,Y,Y,N,N,N),
177    FSUB_D   -> List(Y,d,d,N,Y,Y,N,N,N),
178    FMUL_D   -> List(N,d,d,N,Y,Y,N,N,N),
179    FMADD_D  -> List(N,d,d,N,Y,Y,N,N,N),
180    FMSUB_D  -> List(N,d,d,N,Y,Y,N,N,N),
181    FNMADD_D -> List(N,d,d,N,Y,Y,N,N,N),
182    FNMSUB_D -> List(N,d,d,N,Y,Y,N,N,N),
183    FDIV_D   -> List(N,d,d,N,Y,Y,Y,N,N),
184    FSQRT_D  -> List(N,d,d,N,Y,Y,N,Y,N)
185  )
186
187  val table = single ++ double
188
189  val decoder = DecodeLogic(io.instr, default, table)
190
191  val ctrl = io.fpCtrl
192  val sigs = Seq(
193    ctrl.isAddSub, ctrl.typeTagIn, ctrl.typeTagOut,
194    ctrl.fromInt, ctrl.wflags, ctrl.fpWen,
195    ctrl.div, ctrl.sqrt, ctrl.fcvt
196  )
197  sigs.zip(decoder).foreach({case (s, d) => s := d})
198  ctrl.typ := inst.TYP
199  ctrl.fmt := inst.FMT
200  ctrl.rm := inst.RM
201
202  val fmaTable: Array[(BitPat, List[BitPat])] = Array(
203    FADD_S  -> List(BitPat("b00"),N),
204    FADD_D  -> List(BitPat("b00"),N),
205    FSUB_S  -> List(BitPat("b01"),N),
206    FSUB_D  -> List(BitPat("b01"),N),
207    FMUL_S  -> List(BitPat("b00"),N),
208    FMUL_D  -> List(BitPat("b00"),N),
209    FMADD_S -> List(BitPat("b00"),Y),
210    FMADD_D -> List(BitPat("b00"),Y),
211    FMSUB_S -> List(BitPat("b01"),Y),
212    FMSUB_D -> List(BitPat("b01"),Y),
213    FNMADD_S-> List(BitPat("b11"),Y),
214    FNMADD_D-> List(BitPat("b11"),Y),
215    FNMSUB_S-> List(BitPat("b10"),Y),
216    FNMSUB_D-> List(BitPat("b10"),Y)
217  )
218  val fmaDefault = List(BitPat("b??"), N)
219  Seq(ctrl.fmaCmd, ctrl.ren3).zip(
220    DecodeLogic(io.instr, fmaDefault, fmaTable)
221  ).foreach({
222    case (s, d) => s := d
223  })
224}
225